Designing for a badge, not a poster
A badge gives you a few centimeters to work with, and a chunk of that is already spoken for — a lanyard clip or punched hole at the top, sometimes a fold line if the badge is a folded card. Position the code on a flat, uninterrupted section, usually the lower third, well clear of the hole and away from where the badge folds.
Keep the design itself simple: a shorter destination link means fewer modules in the pattern, which matters more at small sizes. Stick to high contrast and leave a real quiet-zone margin around the code even though space is tight — a code crammed edge-to-edge against text or a logo is harder for a phone camera to lock onto.
vCard or LinkedIn — decide before you print
A vCard link is the standout choice for a badge specifically because the whole point of scanning it is instant contact exchange. One scan, one tap to save, and the recipient has a full contact card — name, phone, email, company — without typing anything. A generic company homepage doesn't do that; it just adds a step between the scan and the actual thing people at a networking event want, which is your contact info.
Some attendees would rather point people to a LinkedIn profile instead, and that's a fine call too — both are static QR content types QRSen supports. The thing to nail down is which one you're using before the badges go to print, since the destination is baked into the code itself and can't be swapped afterward.
Printing in bulk, on a deadline
Badge printing is often handed to an event company running hundreds of badges on a tight turnaround, which means a placement or sizing mistake shows up on every single one, not just yours. Test-print one badge first and actually scan it — with a couple of different phones, under lighting close to what the event floor will have — before signing off on the full batch.
For a scalable badge template, SVG hands off cleanly to a print vendor's design software. For a simpler flat file, PNG or JPG at HD resolution (2048×2048px) works fine too — either way, keep the file simple, since a small badge print area doesn't leave much room for a heavily detailed code to hold up.